The present invention relates to a method for grinding a flat plate by the cutting action of a grinding wheel across the thickness of the plate.
Heretofore, grinding of flat surfaces of a hard, brittle work (1), like silicon and glass, has been accomplished by the use of a ring-shaped grinding wheel (2) attached to the lower open end of an inverted revolving cup (10) as shown in FIG. 1 (a). This conventional method has a drawback that grinding has to be repeated until the work is ground to a desired thickness. In other words, the conventional grinding wheel (2) having its side and bottom extending at right angles to each other grinds the work with both its side and bottom. In such a grinding mode, there is a great contact area that generates a large amount of friction heat thereby impairing the dimensional accuracy of the work due to thermal expansion, and loading of the pores of the grinding wheel with chips is likely to occur, resulting in dulling, burn marks, and grinding cracks. In addition, the cutting edge of the grinding wheel (2) becomes dull during grinding, causing the grindstone to lose proper contact with the work. This makes it difficult to grind the work with one pass, and makes it necessary to repeat the grinding bit by bit in order to grind the work to a desired thickness. In another type of conventional grinding wheel, the bottom is tapered inwardly as shown in FIG. 1 (b). This grinding wheel still has a large contact area and easily loses its sharpness, thereby making it necessary to regenerate the taper.